To develop a model for estimating the time delay between last heroin consumption and blood sampling in chronic drug users. Eleven patients, all heroin inhalers undergoing detoxification, were included in ... [more ▼]

To develop a model for estimating the time delay between last heroin consumption and blood sampling in chronic drug users. Eleven patients, all heroin inhalers undergoing detoxification, were included in the study. Several plasma samples were collected during the detoxification procedure and analyzed for the heroin metabolites 6-acetylmorphine (6AM), morphine (MOR), morphine-6-glucuronide (M6G) and morphine-3-glucuronide (M3G), according to a UHPLC/MSMS method. The general linear mixed model was applied to time-related concentrations and a pragmatic four-step delay estimation approach was proposed based on the simultaneous presence of metabolites in plasma. Validation of the model was carried out using the jackknife technique on the 11 patients, and on a group of 7 test patients. Quadratic equations were derived for all metabolites except 6AM. The interval delay estimation was 2–4 days when only M3G present in plasma, 1–2 days when M6G and M3G were both present, 0–1 day when MOR, M6G and M3G were present and <2 h for all metabolites present. The ‘jackknife’ correlation between declared and actual estimated delays was 0.90. The overall precision of the delay estimates was 8–9 h. The delay between last heroin consumption and blood sampling in chronic drug users can be satisfactorily predicted from plasma heroin metabolites. [less ▲]

A gradient reversed phase high-performance liquid chromatography (RPHPLC) method with ultraviolet (UV) detection to analyze hydrochlorothiazide (HCT) and valsartan (VS) simultaneously in a tablet formulation during forced degradation studies was developed. This method was validated using a novel approach, namely, the accuracy profile or total errors approach. The robustness of the method was evaluated using a Plackett–Burman design for eight factors. The algorithm of Dong was applied to determine the significant factor effects. The validation results showed that the method is precise (RSD: 1.14% for HCT and 0.43% for VS) and accurate (mean recovery: 99.90% for HCT and 99.98% for VS). On the other hand, the results of the robustness study showed that the type of column was the important factor which affects a number of responses, namely, the asymmetry factor (AF), retention time (RT), and resolution (RS). However, the assay results were not affected; therefore, the method can be considered robust. Finally, the method was applied to study the stability of HCT and VS under forced conditions. Significant results were obtained with basic hydrolysis, oxidation, and thermal stress, while the accelerated and acidic conditions did not affect the stability of HCT or VS. [less ▲]

As serious but neglected public health problems, poor quality medicines, i.e. for antimalarial medicines, urged to be fought. One of the approaches is to consider the analytical chemistry and separative ... [more ▼]

As serious but neglected public health problems, poor quality medicines, i.e. for antimalarial medicines, urged to be fought. One of the approaches is to consider the analytical chemistry and separative techniques. In this study, a generic liquid chromatographic method was firstly devel-oped for the purpose of screening 8 antimalarial active ingredients, namely amodiaquine (AQ), piperaquine (PPQ), sulfalene (SL), pyrimethamine (PM), lumefantrine (LF), artesunate (AS), artemether (AM) and dihydroartemisinine (DHA) by applying DoE/DS optimization strategy. Since the method was not totally satisfying in terms of peak separation, further experiments were undergone applying the same development strategy while splitting the 8 ingredients into five groups. Excellent prediction was observed prior to correlation between retention times of predicted and observed separation conditions. Then, a successful geometric transfer was realized to reduce the analysis time focusing on the simultaneous quantiﬁcation of two WHO's recommended ACTs in anti-malarial fixed-dose combination (AM-LF and AS-AQ) in tablets. The optimal separation was achieved using an isocratic elution of methanol-ammonium formate buffer (pH 2.8; 10mM) (82.5: 17.5, v/v) at 0.6ml/min through a C18 column (100mm×3.5mm, 3.5 μm) thermostated at 25°C. After a successful validation stage based on the total error approach, the method was applied to determine the content of AM/LF or AS/AQ in seven brands of antimalarial tablets currently marketed in West, Central and East Africa. Satisfying results were obtained compared to the claimed contents. [less ▲]

In the framework of fighting against the poor quality medicines sold in developing countries using classical analytical methods easily accessible in those countries, four UV-Visible spectrophotometric ... [more ▼]

In the framework of fighting against the poor quality medicines sold in developing countries using classical analytical methods easily accessible in those countries, four UV-Visible spectrophotometric methods for one antimalarial (quinine) and two antibiotics (amoxicillin and metronidazole) have been developed and validated according to the total error strategy using the accuracy profiles as a decision tool. The dosing range was 2-10µg/mL (for quinine sulfate in tablet), 4-12µg/mL (for quinine bichlorhydrate in oral drop - metronidazole benzaote in oral suspension) and 15-35µg/mL (for amoxicillin trihydrate in capsule). The validated methods were then applied in determining the content of some analogous medicines sold in the Democratic Republic of Congo. Thus, the proposed UV-Visible spectrophotometric methods are simple and suitable to quantify quinine, amoxicillin and metronidazole in different pharmaceutical forms. [less ▲]

Newly developed drugs often have poor bioavailability due to their poor water solubility (BCS class 2 drugs). It is therefore necessary to develop new strategies to enhance their solubility and their ... [more ▼]

Newly developed drugs often have poor bioavailability due to their poor water solubility (BCS class 2 drugs). It is therefore necessary to develop new strategies to enhance their solubility and their activity, among which, Self-Emulsifying Drug Delivery System (SEDDS). The efficacy of the drugs contained in these preparations is mainly affected by the solid state and the particle size of the active pharmaceutical ingredient (API). However, it is quite complex, long and expensive to characterize these parameters with classical techniques such as X-Ray powder diffraction, differential scanning calorimetry or hot stage microscopy. The present article presents, through a case study, the advantages of the Raman hyperspectral imaging in the characterization of such formulations. Indeed, Raman chemical imaging may fully characterize SEDDS with single equipment and operator in a non-destructive way allowing the follow-up of the formulation during stability studies. Raman imaging is therefore a tool of choice in the PAT framework since it increases the knowledge of the formulation and the process. A quantitative multivariate method using Raman hyperspectral imaging to assay the API in the lipid based formulation has been developed and fully validated following the “total error” approach. [less ▲]

A selective and sensitive electroanalytical method was developed for arsenic determination based on a nanogold (AuNP) modified solid carbon paste work- ing electrode (SCPE) modified in two steps (i ... [more ▼]

A selective and sensitive electroanalytical method was developed for arsenic determination based on a nanogold (AuNP) modified solid carbon paste work- ing electrode (SCPE) modified in two steps (i) physisorp- tion and (ii) additional electrodeposition of nanogold par- ticles in the presence of iodide. Copper(II) interference was solved by covering the gold layer by a self assembled mono layer (SAM) of glutathione. Using DPASV a linear response of the signal was obtained as a function of As(III) in the concentration range 0.05–20mM (4– 1498 ppb) with a limit of detection of 0.01 mM (0.9 ppb). Sample stirring and degassing were not needed. Applica- tion to the determination of arsenic(III) and (V) in un- derground water samples from Burkina Faso was success- fully achieved. [less ▲]

Raman hyperspectral imaging is an increasingly used tool in the pharmaceutical field because it allows for the investigation of many characteristics on a solid sample. This paper delves into Raman ... [more ▼]

Raman hyperspectral imaging is an increasingly used tool in the pharmaceutical field because it allows for the investigation of many characteristics on a solid sample. This paper delves into Raman spectroscopy and imaging, including spectral and spatial information, and presents some applications of Raman hyperspectral imaging in the pharmaceutical field. [less ▲]